Contacting tray deck assembly



Nov. 18, 1958 J. 5. WILSON 2,860,860

, CONTACTING TRAfnEcK ASSEMBLY Filed Oct. 25, 1952 2 Sheefas-Sheet l ilk-Man lib l'i P 513111111111 gwlllr \nverfi-or':

Joseph GANHson s M/a 221% His. A++orneq 2 Sheets-Sheet 2 J. 'G. Wl LSON CONTACTING TRAY DECK ASSEMBLY ri Pllf D L .IIIIIIII Nov. 18, 1958 Filed Oct. 25, 1952 lnven'for' Joseph G. Wilson By His A++orney \\\\\\\\\\\\w F IG 4.

United States Patent CONTACTING TRAY DECK ASSEMBLY Joseph G. Wilson, St. Louis, Mo., assignor to Shell Development Company, Emeryville, Calif., a corporation of Delaware Application October 25, 1952, Serial No. 316,895

4 Claims. (Cl. 261-113) This invention relates to tray decks for gas and liquid contact columns, such as fractionation, distillation, absorption and gas scrubbing towers, wherein ascending gas is brought into contact with descending liquid at each of a plurality of superposed trays (the term gas being used herein to include vapor). The invention is particularly concerned with an improved tray deck assembly comprising a plurality of individual fractional deck sections for each tray and with the individual deck sections themselves.

It is an important object of the invention to provide a tray deck assembly wherein the individual fractional sections of the deck are removable to provide a manway through the column while other sections are left in place, the construction being such that the remaining sections have sufficient strength to avoid the danger of bending when a workman steps on the edge of the remaining section although the section is 'made of comparatively thin stock, e. g., sheet metal. Ancillary thereto, it is an object to provide an individual fractional de'ck section that can be mounted between two horizontal beams that are mounted within the interior of the column, said deck sections being constructed of thin material and shaped to provide a structure that will not be distorted or deflected beyond permissible limits due to the weight of liquid that collects on the tray, normal pressure differentials between inter-tray spaces, or to other loads, such as those of workmen, although thesections contain numerous perforations distributed over the area thereof and tending to weaken them.

Another object is to provide a tray deck assembly wherein the tray deck has punched openings, e. g., slots, for the upward flow of gas and the downward flow of liquid, the individual deck' sections having longitudinal and transverse reinforcements arranged to provide large areas in the deck plates for the openings, whereby the deck sections can be made of thin metal and the openings can be punched in rows by repeated movements of a single die or punch, or a battery of dies or punches, thereby providing for a construction that is more economical as regards labor and materials than prior tray assemblies.

Still another object is to provide a tray deck assembly wherein'the individual, fractional tray deck sections have outlines that are as far as possible identical, whereby a small number of differently shaped outlines may'be used in the column, thereby further simplifying the procurement of the sections and avoiding the necessity of storing a great variety of such sections for replacement or for new installation. More specifically, it is an object to provide a construction wherein all fractional tray deck sections except those adjoining the column wall are of congruent rectangular outlines (the term rectangular being used to include square). Ancillary thereto, it is an object to provide a tray deck assembly wherein all deck sections are of size and outline to permit them to be moved verti-' cally through the column, preferably through the vertical manways provided when one of such sections is removed from each tray deck assembly, and through the usual I manway opening at the side of the column.

a modification.

Further objects will become apparent from the following description.

In summary, according to the invention, the individual tray deck sections are made of perforated thin sheet material and have longitudinal margins resting on horizontal supporting beams that extend across the columnat each tray level, each tray having suitable openings for the passage of material to be contacted and the margins thereof being preferably releasably secured to the beams, .the deck sections having transverse stiffening flanges ex- .tending between the beams, preferably beneath the tray deck. In the preferred embodiment, each fractional deck section has one or more stiffening beams extending par- ,allel to the supporting beams intermediate thereto, so as to provide at least two vertically unobstructed areas between the supported margins and the stiifening beams, .and the perforations are situated in each of said areas.

These perforations punched slots that extend transversely, e. g., perpendicuor openings are advantageously larly or obliquely, to the beams and are arranged in rows parallel to the beams. Tray deck sections adjacent to the column walls have correspondingly curved margins .which rest on an annular support member, such as a ring secured to the column wall.

The invention will be described in detail with reference to the accompanying drawings forming a part of this specification and showing one preferred embodiment thereof, wherein:

.tion;

Figure 1 is an elevation view, partly in section, of a Figure 2 is an enlarged horizontal sectional view, taken on line 2-2 of Figure 1, showing the geometric arrange- 35 .ment of the fractional deck sections in the tray assembly;

showing the connection of the margin of the deck section Figure 3 is a further enlarged detail, in vertical section,

fractional deck sections;

45 tion taken on broken line 6+6 of Figure 5;

Figure 6 is a transverse sectional view of the deck sec- Figure 7 is a fragmentary sectional view taken online 7'-7 of Figure 5;

Figure 8 is an enlarged fragmentary sectional view, taken on line 8-8 of Figure 2, showing a typical fastener for a fractional deck section at the manway location; and

Figure 9 is a sectional view similar to Figure 7 showing Referring to the drawings in detail, the tank or column 10 provides vertical, closed side walls and upper and lower end walls 11 and 12, having a vapor outlet 13 and a bottoms outlet 14, respectively. Suitable inlets for vapor and liquid, such as inlets 15 and 16, may be'provided as required at desired levels and equipped with distributors, not shown. The column has at the side thereof one or more manways 17, each having a removable closure 18, which may be bolted on as indicated at 18a, such manways being typically 20 inches in internal diameter. The invention deals primarily with the tray deck assembly within the column, and it is, therefore, unnecessary to describe further the means for admitting and discharging fluids to be contacted, which include the usual valves and auxiliary equipment. i 1

A series of annular support rings 20, each providing an upper load-supporting face, are mounted within .the column in vertically spaced relation corresponding'to the positions of the trays; these rings may be welded or otherwise secured to the column wall. A plurality of horizontal support beams 21 are mounted in parallel and horizontally spaced relation for each tray deck. These beams may be of any suitable type, such as structural channels laid with the flanges horizontal, the upper flanges 21a (see Figs. 4 and 8) of each beam forming an upper loadsupporting face that is horizontally aligned with the loadsupporting face of the corresponding support ring. These beams may be secured within the column in any desired manner, e. g., by being attached to the support rings as shown in Figs. 2 and 4 by means of removable clamps, as shown. Thus, each clamp may comprise an upper and a lower clamp member 22 and 23, respectively, connected by a screw bolt 24 which extends through the upper clamp member, and has a threaded engagement with the lower clamp member; if desired the upper flange 21a may be notched as indicated at 25 to accommodate the bolt without engagement. The lower parts of the upper clamp member 22 engage the upper surfaces of the ring 20 and flange 21a directly, being emplaced prior to attachment of the deck sections to be described presently. The beams 21 are disposed parallel to each other and are uniformly spaced horizontally to divide the cross-sectional area of the column into laterally contiguous open panels of equal widths that are preferably somewhat less than the internal diameter of the manway 17. By way of example, the beams 21 may have the upper flanges 21a and the bottom flanges 21b two inches wide and may be positioned twenty inches center to center (equal to the internal diameter of the manway 17), thereby leaving open panels eighteen inches in width. Three beams, providing for each tray assembly two intermediate and two outside panels (the latter being bounded laterally in part by the ring 20) are used in the illustrative embodiment, which is intended to represent a column eighty inches in internal diameter. The upper flange 21a of the beam is pierced at uniform intervals along the length of the beam at the center line of the flange as indicated in Fig. 4 at 26 (ex cept at the vertical manway location, opposite the section 28a, Fig. 2, as explained below), and the holes are tapped to receive bolts 27 for holding down the tray deck sections, to be described. The beams of each tray are preferably installed at right angles to the beams of adjacent trays, as indicated in Figure 1.

Referring to Fig. 2, the composite tray has a plurality of fractional deck sections. All sections except those adjoining the column wall are preferably of identical, rectangular outline and are designated by the number 28 or 28a, four of such sections being illustrated; the other sections, indicated by the number 29 or 29a, are sketch sections, i. e., they have two or three straight margins, respectively, and a curved margin to conform approximately to the outline of the column, the curved margins having a radius of curvature somewhat less than that of the column to permit the sections to be mounted with some clearance as indicated in Fig. 3. The complete deck sections have lengths (the term length being used to denote a dimension parallel to the beams 21) not exceeding half the column diameter and, preferably, about the same as or slightly less than the width of the deck section, e. g., 17.5 inches. Some of the sketch sections in the central panels, e. g., section 29a, may have slightly greater lengths and their longer longitudinal margins extend to and overlie the support ring 20. Each deck section has a width that is sufficient to span one panel between support beams, e. g., 19.25 inches, whereby the longitudinal margins or edge portions thereof may rest on adjacent beams. To obviate the need for precision fitting and to avoid the danger of buckling of the plates due to thermal expansion of the sections, the widths are advantageously slightly less than the distance between centers of the beams 21, so as to leave a longitudinal clearance between adjacent deck sections along the center portions of the beams as clearly shown in Fig. 2. This clearance may be made sufficiently wide to accommodate the bolts 27 without contact therewith,.but notches 30, indicated in Fig. 5, may optionally be provided. While the complete, rectangular sections 28 are supported only at their longitudinal margins which rest on the beams, the sketch sections 29 overlie the support ring 20 and receive support from it. For the same reasons, the curved margins of the sketch deck sections 29 and 2911 are spaced from the wall of the tank 10, as shown clearly in Figs. 2 and 3.

Each deck section is held down by releasable fasteners of any approved type. As shown in Figs. 2 and 4, each hole 26 in the flange 21a receives a bolt 27 which, when tightened, forces a washer 31 against the upper faces of the edge portions of two adjacent deck sections, thereby clamping them frictionally against the beams, the washers being sufficiently wide to span the clearance between adjacent sections. The washers at the corners of the sections engage four sections. As shown in Figs. 2 and 3, the edge portions of the sketch sections 29 resting on the ring 20 are similarly clamped by releasable means including a bolt 32 having a threaded engagement with a tapped hole in the support ring and pressing against a lug 33 having a lower flange 34 equal in thickness to that of the edge of the deck section. These fasteners are placed at intervals circumferentially about the ring, only some of them being shown in Fig. 2.

At least one of the deck sections, preferably a complete, rectangular section, indicated at 28a, is preferably provided with fasteners that can be actuated both from the top and from the bottom of the tray to provide a vertical manway through the tray when the section is removed; the deck section itself is of construction identical with that of the other sections. Such fasteners are indicated in Fig. 2 at 35, and may be of any suitable design and are known in the art (see, for example, U. S. Patent No. 2,332,243 to McCarthy). According to one specific arrangement, shown in Fig. 8 for purposes of illustration, a small rectangular plate 43 is welded to the fastening bolt 42, which extends through an oversize hole in the flange 21a. The plate 43 has a vertical dimension equal to or somewhat less than the thickness of the deck section and is elongated in a direction parallel to the beam, being narrow enough to fit into the interval between adjacent deck sections with clearance, as shown; it thereby prevents rotation of the bolt. The bolt is $6 cured by nuts 44 and 45, the latter of which retains a washer 41 (shown rectangular to distinguish it from the washers 31) which is large enough to span the interval between the margins of adjacent deck sections and clamp the latter against the beam. It is evident that the deck section 28:: may be fastened or unfastened either from the bottom or from the top by manipulation of either the nut 44 or 45. In fastening the section from the top the bolt 42 is inserted into the flange hole from the top and the lower nut 44 is tightened before emplacing the section 28a. When working from the bottom the bolt 42, with the washer 41 and nut 45 attached, may be initially supported above the final position by support means (not shown) pushed upwards through the flange holes; when the section 28a is subsequently emplaced, e. g., by sliding it longitudinally, the bolts can be lowered into the position shown in Fig. 8 and tightened by applying the nuts 44.

Referring to Figs. 5-7, each deck section 28 is formed of a single plate of sheet material which may be thin, e. g., 12 gauge (0.107 inch) although other thicknesses may be used, c. g., 16 gauge (0.065 inch). The section provides a flat central portion and longitudinal margins or edge portions 36 and 37 which are coplanar with the central portion, whereby the upper face of the section is entirely flat and the undersides of the margins are likewise flat to rest on the beams. A longitudinal stiffening beam 38 is secured to the underside of the section in spaced relation to the margins to divide the central portion into longitudinal, vertically unobstructed areas A and B. This beam preferably extends the full length of the deck section and is fixed to the plate at a plurality of points along the length thereof by continuous or spot welding. The deck section is made from a plate initially longer than the finished length of the'section and the end portions are bent downwards over the ends of the stiffening beam 38 as indicated at 39 to provide a trans verse vertical stiffening flange. Each flange preferably has the lower edge thereof bent under the stiffening beam to provide a horizontal lip 40 in supporting engagement with the beam. Each flange 39 and its lip 40 extends preferably the 'full distance between supporting beams or between a beam and the ring 20 with slight clearance (see Fig. 8) but does not extend beneath the edge portions 36 and 37, whereby the saidedge portions are free to rest on the load-supporting faces of the beams and the transverse flanges lie entirely below said faces.

The construction of the sketch deck sections 29 and 29a is similar to that described for the complete sections, with the exception that they have only one transverse flange along the straight transverse edge; the margin opposite to the flan ges transverse edge is curved and receives support from the supportring 20. The stiffening beam 38 in these sketch sections'fterminates short of the curved margins to permit the latter to overlie the support ring.

Each of the areas A and B of the central portion of the section is perforated to provide two rows of slots 46. Only some. of these slots are'indicated in Fig. 5, and the slots are indicated only on two of the sections of Fig. 2, wherein chain dotted rectangles C, D, E and F are used to indicate rows of slots on other deck sections. The widths and intervals of these slots will be determined by the specific service to which the column is to be put and forms no part of this invention; it may be stated, however, that such slots are typically between about 0.1 and 0.6 inch in width and are spaced apart to provide an aggregate slot area throughout the tray that is between 7% and 50% or even more of the total tray area. Such slots are conveniently punched into the plate by a die or punch prior to attaching the stiffening beam 38 and bending the transverse edges to form the flanges 39. Although the tray sections disclosed are particularly suited for such slots when the latter extend transversely to the beams, as shown, the invention is not limited to this arrangement, and openings of other shapes may be provided. It will be understood that in the embodiment shown the trays have no downcomers for liquid, and the said perforations constitute the only openings through the trays for the upward flow of gas and the downward flow of liquid. When the beams are oriented as shown in Fig. 1 the slots on each tray will be perpendicular to the slots of adjacent trays, all slots within the same tray being parallel. These relations are, of course, optional.

It is evident that the beams 21 as well as the several deck sections can be readily installed in the column and removed therefrom through the manway 17, and that the trays can be reached for inspection, cleaning or repair by removing the sections 28a, all of which are in vertical alignment on the several trays. After being unfastened these sections 28a may be raised slightly and pushed horizontally over the sections that remain in place. By tilting, these and other sections can be removed through the vertical shaft or manway resulting from removal of the sections 28, without the need to remove other sections.

By the construction shown the perforated fractional deck sections are adapted to span beams that are spaced apart by considerable distances, as was indicated above, without excessive deflection although the sections are made of thin sheet metal, thereby effecting an important economy. The invention is particularly suitable in connection with trays using slots, sometimes known as grid trays, wherein the long slots tend to weaken the deck and present special difliculty when thin metal, suitable for punching, is to be used. It is further evident that the deck sections can be manufactured economically with few operations.

The edges of the slots need not be truly perpendicular to the deck surface with sharp corners as shown in Figures 6-8, but may have other shapes for altering the flow characteristics of the slots and/or increase the strength of the deck section. In particular, it is often desirable to bend one or both of the edges up or down either subsequent to or during the punching operation, by using suitable dies as is well known. Such a modification is illustrated in Figure 9, which corresponds to Figure 7 and also shows a deck section 28 with a marginal flange 39 and lip 40 turned under the stiffening beam 38. The slots 46a in this case have down-turned lips 46b that extend the full lengths of the slots and produce nozzle-type slots. This construction adds materially to the strength and stiffness of the deck section and is particularly useful when thin sheet metal such as 16 gauge or thinner is used. This makes it practicable to use 18-8 stainless steel (steel containing 18% chromium and 8% nickel), nickel, Monel or other expensive materials in thin sheets for the deck sections.

I claim as my invention:

1. A tray deck section for contacting towers including a plate of sheet metal entirely fiat between the longitudinal edges thereof, whereby marginal strips along said edges are adapted to rest on elongate support means; at .least one longitudinal stiffening beam extending-along the underside of said plate substantially for the full length thereof in spacedrelation to said marginal strips to provide at least two vertically unobstructed longitudinal areas in said plate between said marginal strips and the stifiening beam, said plate having a plurality of openings in each of said unobstructed areas for the passage of material to be contacted; and a downward vertical flange at each transverse edge of the plate, each said flange having the ends thereof terminated short of said marginal strips so as to lie wholly between said support means and having a horizontal lip turned inwardly under said plate and in supporting engagement with a downwardly directed part of the stiffening beam.

2. In a contacting tower, a tray structure comprising: a pair of horizontally spaced support members adapted to be fixed within said tower and having load-supporting faces situated in a common, substantially horizontal plane; a plurality of horizontal tray deck sections of sheet metal supported on said support members, each said section having a fiat central portion'spanning the interval between said support members, a pair of longitudinal edge portions coplanar with said central portion and resting on said load-supporting faces of the support members, at least one longitudinal stiffening beam extending along the underside of the central portion for the full length of the deck section in spaced relation to both said side edges to provide at least two vertically unobstructed longitudinal areas in said central portion between said support members and the stiffening beam, said stiffening beam being fixed to said deck section at least at a plurality of points along the length thereof, a multitude of parallel slots in said central portion extending transversely to said beam and arranged in rows that extend parallel to said beam, there being at least one row of slots in each of said unobstructed longitudinal areas and each of said areas having slots substantially over the full width thereof to provide passages for the materials to be contacted, and a downward vertical flange at each transverse edge of the central portion of the deck section, each said flange extending horizontally substantially the full distance between-said support members, being coextensive in depth with the adjoining part of said stiffening beam, and having at the bottom thereof a horizontal lip turned inwardly under said central portion and in supporting engagement with a downwardly directed part of the stiffening beam; and fastening means on said support members having engage- 7 ment with said longitudinal edge portions for holding said deck sections.

3. A tray deck section for contacting towers comprising a plate of sheet metal so thin as to require auxiliary supports to maintain it in a horizontal plane, said plate having throughout a flat, unobstructed upper face and including a central portion and horizontally spaced longitudinal edge portions coplanar with the central portion and adapted to rest on elongate support means; at least one longitudinal stiffening beam extending along the underside of said plate for the full length thereof in spaced relation to both said edge portions to provide at least two vertically unobstructed longitudinal areas in said plate between said edge portions and the stiffening beam, said stiffening beam being welded to said plate at least at a plurality of points along the length thereof, said plate having a multitude of parallel punched slots extending transversely to said beam and arranged in rows that extend parallel to said beam, there being at least one row of slots in each of said unobstructed longitudinal areas and each of said areas having slots substantially over the full Width thereof to provide passages for the materials to be contacted; and a downward vertical flange at each transverse edge of the plate, each said flange extending horizontally substantially the full distance between the inner limits of said edge portions but not beyond said limits so as to lie wholly between said support beams, being coextensive in depth with the adjoining part of said stifiening beam, and having at the bottom thereof a horizontal lip turned inwardly under said plate and in supporting engagement with a downwardly directed part of the stiflening beam.

4. A tray deck section for fluid contacting towers of the character described including a thin plate of sheet material having a flat central portion, narrow longitudinal mar- {T3 u ginal portions adapted to rest on elongate support means, and integral downward flanges at each transverse edge extending substantially the whole distance between but terminating short of said longitudinal marginal portions; at least one separate, longitudinal stiffening beam engaging the underside of said central portion, said stiffening beam extending substantially the full length of the plate in spaced relation to both said longitudinal marginal portions and dividing the central portion into a plurality of vertically unobstructed, longitudinal areas, said plate having a plurality of openings in each of said vertically unobstructed, longitudinal areas for the passage of fluids to be contacted; and means securing said stiffening beam to the plate including a lip on at least one of said downward flanges turned under the plateand in supporting engagement with a downwardly directed part of the stifiening beam.

References Cited in the file of this patent UNITED STATES PATENTS 965,366 Bradley July 26, 1910 986,422 Bettendorf Mar. 7, 1911 1,965,549 Holmes et al July 3, 1934 2,210,808 Glitsch Q Aug. 6, 1940 2,320,073 Gibb May 25, 1943 2,321,719 West June 15, 1943 2,491,726 Glitsch Dec. 20, 1949 2,582,826 Glitsch Q. Jan. 15, 1952 2,611,457 Glitsch Sept. 23, 1952 2,611,596 I Glitsch Sept. 23, 1952 FOREIGN PATENTS 181,095 France Ian. 24, 1887 801,473 Germany Jan. 8, 1951 988,714 France May 9, 1951 

